I waited a long time for R16 and hoped for a "better" UI in the way, to respect the mandatory accessibility support for people with eye disabilities.
Windows has for those people like me the high-contrast-mode and high-contrast-themes - e.g. high-contrast-*1.

In the MSDN guide lines is written, that an enabled high-contrast-mode means for applications to stop using their own color themes, corporate design etc. and to use mandatorily the system colors.

In my case the dialogs would be black in the background, would have yellow text and white "borders".

Here you see the installer, the control center, the encodings and settings windows in the black-yellow high-contrast:

2016-06-20_11-44-03-dBpoweramp_ Advanced.png2016-06-20_11-42-26-dBpoweramp_ Codecs.png2016-06-20_11-42-02-dBpoweramp Control Center.jpg2016-06-20_11-41-34-dBpoweramp Installer.png

The R15 issues are still the same! There is no real revamp of the UI!

There is still a too big mixture of "owner-drawn" controls, native controls, icon sets optimized for light backgrounds, etc..
DPI awareness is not the only thing to think of, since even many users of AMOLED devices want to use dark designs, even with Windows 10 on mobile devices.

I expected a lot of more and I fear, there will not be any real assistance or support for accessibility? Right?

Losing hope a bit.